Abstract

Magnetic rotational spectroscopy was employed for rheological analysis of nanoliter droplets of butterfly saliva. Saliva viscosity of butterflies is 4–5 times greater than that of water and similar to that of 30%–40% sucrose solutions at 25 °C. Hence, viscosity stratification would not be expected when butterflies feed on nectar with 30%–40% sugar concentrations. We did not observe any viscoelastic effects or non-Newtonian behavior of saliva droplets. Thus, butterfly saliva is significantly different rheologically from that of humans, which demonstrates a viscoelastic behavior.

Received 15 October 2012Accepted 04 January 2013Published online 23 January 2013

Acknowledgments:

We thank Matthew Lehnert for helping capture butterflies. The authors are grateful for the financial support of the National Science Foundation through Grants EFRI 0937985, DMR REU 1062873, and of the Air Force Office of Scientific Research through Grant DURIP FA9550-11-1-0316.